Lining for hydrocarbon treating apparatus



y 1944- c. WEIZMANN ET AL 2,354,163

' LINING FOR HYDRQCARBON TREATING APPARATUS Filed May '7, 1945 in?) 61210129 C, 11? 6 a zrmjzfl/ %,ZZ. 5i 017/62 Patented July 18, 1944 UNITED STATES PATENT OFFICE Charles Weizmann, London, and Herbert Steiner,

Eccles, England Application May 7, 194:, Serial No. 486,060

r In Great Britain August 8, 1941 1 Claim (01. 19H

This invention relates to the construction of plants for the thermal treatment of materials comprising hydrocarbons in the vapour phase, which term includes the cracking of oils and tars, the aromatisation of aliphatic oils, the destruction hydrogenation of carbonaceous substances of the nature of oils, tars and coals and their distillation and conversion products, and the polymerisation of unsaturated hydrocarbons, such as ethylene and its homologues and acetylene.

The term plants" includes also tube stills, transfer lines and other parts of or parts associated with distillation plants and reaction chambers for purposes such as those indicated above.

When cracking hydrocarbons in the vapour phase, especially between the comparatively usual range of say temperatures between about 450 C. and about 700 6., carbon deposits are commonly obtained. This applies either to catalytic or noncatalytic processes.

It has already been proposed to carry out thermal treatments as aforesaid in the vapour phase in apparatus the hot parts of which consist of, or are coated with, materials which prevent or strongly suppress the deposition of carbon. A whole series of substances has been suggested for this purpose, as for example elements of the 4th group of the periodic system, such as silicon, carbon in the form of graphite, tin and lead and also chromium and the like including copper.

It has also been proposed for the purpose of preventing the deposition of carbon to supply the metallic parts of the apparatus with metalloids such as boron, arsenic, antimony and bismuth.

Further, it has been found that the thermal treatment of a material comprising hydrocarbons in the vapour phase is carried out with particular advantage in apparatus the parts of which coming into contact with the hot reaction materials are provided with a lustrous metal coating which prevents or strongly suppresses the deposition of carbon and which is obtained by the decomposition of volatile metal compounds, in particular those containing carbon. Asmetal compounds of the said kind may be mentioned, for example,

. carbonyls and metal alkyls, as for example molybdenum carbonyl, iron carbonyl and lead tetraethyl.

The substrata for the coatings may be of any metal stable at the temperature employed in the reactions concerned as for example copper, iron,

ordinary steel, special steels or iron-free alloys- (such as that metal sold in the trade under the name Monel), brass and bronze.

oxide on the inside surface, and has afterwards been reduced by treatment with hydrogen, hydrocarbons or any other reducing agent, such as alcoholsor aldehydes so as to produce a matt or porous surface. Under certain conditions the formation of carbon sets in only in the later stages of the cracking reaction, in which case in certain circumstances it may only be necessary to coat certain parts of the total cracking plant with copper.

The invention consists in a plant or apparatus for the thermal treatment of materials comprising hydrocarbons in the vapour phase, and therefore liable to give carbon deposits, wherein copper is used as a lining, the copper being in the form of pure copper and forming the inner surface of the tube or vessel or being used as a coating thereon, in which the copper surface is obtained by way of an oxidised copper surface subsequently reduced.

The invention also consists in plants or apparatus for the purpose referred to above substantially as described below.

The accompanying diagrammatic drawing shows, as to Figure l a reaction vessel, and as to Figure 2 a tube lined in accordance with the present invention. 1

In carrying the invention into effect in the form illustrated in Figure 1, the reaction vessel a made of iron or steel or alloys of these metals according to common practice, is lined on its inner surface with a layer of copper b applied in any suitable way, for instance, by electrolytic deposition from an alkaline cyanide solution. The lining is shown applied to the side of the vessel, the base and the cover. The copper is then subjected to oxidation forming a layer of copper oxide on the surface and this oxide is then reduced by treatment with hydrogen, hydrocarbons or any other reducing agent, such as alcohpls or aldehydes, so as to produce a matt or porous surface.

As shown in Figure 2, the wall to be lined is that of a tube 0 made of iron or steel or alloys of these metals, and the lining marked dis similar to the lining b referred to above.

General Among other methods of supplying the copperlining may be mentioned covering the inside of the reaction vessel to be lined with a. sheet of copper of the same form. The activation of the copper surface by successive oxidation and reduction may be effected by passing over the surface at a suitable temperature of between 250 and 600 C. a current of oxygen air, or an oxygen containing gas, and then at a temperature of between 200 and 300 C. reducing gas.

We claim:

In the thermal treatment of hydrocarbons in the vapor phase in metallic apparatus at temperatures sufliciently high to normally cause the deposition of carbon in the apparatus, the improvement which comprises employing a reaction apparatus having an inner surface of copper exposed to the hydrocarbons undergoing treatment and, prior to the reaction, oxidizingsaid copper surface and then reducing it to metallic copper, thereby producing a porous, matt surface; whereby carbon deposition on said surface is substantially eliminated.

CHARLES WEIZMANN. HERBERT STEINER. 

